PONTIAC SLP

iTrader: (3)

hi , today i went to the Dyno to tune my car , we pulled three times the car runs lean above 5000 RPM A/F 15-16 , i don't know why it runs lean !! i installed Walbro 255 fuel pump before 1 week , what is the problem ?

please guys help me

Dabeztz28

iTrader: (27)

Stock fuel harness? Whats your setup?

mr_biscuitz

iTrader: (22)

mine did the same exact thing but I have a little more done than you. I would also like to know whats up. Im adding another pump but would like to hear what everyone thinks about yours so I can check mine also. Good luck!

mr_biscuitz

iTrader: (22)

I have a 255 intank w/hotwire kit, 60lb injectors, stock lines and rails. tr224, full boltons w/12 bolt, and d1sc. Car made 565hp at 5200rpm due to it leaning out. The guy tuning it said I needed to add another pump, which I ordered already but also wanting to hear what everyone else thinks. Thanks and not trying to hijack the thread but it sounds like we are having the same exact problems.

PONTIAC SLP

iTrader: (3)

i think walbro pumps is bad , my mods , MS4 112 , fast 90 with 90 t/b , full exhaust , 4.10 gears , 150 wet kit , but we did't sprayed at the dyno

SmurfLSX

iTrader: (9)

whats the duty cycle on the injectors ? or its only a matter of time before it blows up going that lean. Please tell me its not a stock tune.

Magic Man

Do you still have the stock injectors?Outside of suppling fuel the pump doesn't have much to do with it running lean looks like you need bigger injectors or get the tune setup to increase pulse width.

PONTIAC SLP

iTrader: (3)

problem fixed , i changed the fuel pump same as mine walbro 255

Old Geezer

iTrader: (3)

Fuel psi was, when the pull[s] were made?